vendor issue in sub work order fixed

lib/views/pages/sub_workorder/create_sub_workorder_page.dart

@@ -251,7 +251,7 @@ class _CreateSubWorkOrderPageState extends State<CreateSubWorkOrderPage> {
                             SingleItemDropDownMenu<SupplierDetails, VendorProvider>(
                               context: context,
                               title: context.translation.vendorEng,
-                              initialValue: _subWorkOrders.supplier,
+                              initialValue: _subWorkOrders.supplier ?? initialSupplier,
                               onSelect: (supplier) {
                                 if (supplier != null) {
                                   _subWorkOrders.supplier = supplier;
@@ -265,8 +265,8 @@ class _CreateSubWorkOrderPageState extends State<CreateSubWorkOrderPage> {
                             SingleItemDropDownMenu<SuppPersons, NullableLoadingProvider>(
                               context: context,
                               title: context.translation.vendorName,
-                              enabled: _subWorkOrders.supplier?.suppPersons?.isNotEmpty ?? false,
-                              staticData: _subWorkOrders.supplier.suppPersons,
+                              enabled: _subWorkOrders?.supplier?.suppPersons?.isNotEmpty ?? false,
+                              staticData: _subWorkOrders?.supplier?.suppPersons,
                               onSelect: (suppPerson) {
                                 if (suppPerson != null) {
                                   engineer = SuppEngineerWorkOrders(
@@ -396,8 +396,9 @@ class _CreateSubWorkOrderPageState extends State<CreateSubWorkOrderPage> {
   }
 
   bool checkVendorFieldsVisibility(Lookup callsLastSituation) {
-    bool result = /*(_subWorkOrders.supplier?.suppliername?.isNotEmpty ?? false) ||*/
-        (callsLastSituation?.name?.toLowerCase()?.contains("under repair-vendor") ?? false) || (callsLastSituation?.name?.toLowerCase()?.contains("waiting for vendor") ?? false);
+    bool result = (initialSupplier?.suppliername?.isNotEmpty ?? false) ||
+        (callsLastSituation?.name?.toLowerCase()?.contains("under repair-vendor") ?? false) ||
+        (callsLastSituation?.name?.toLowerCase()?.contains("waiting for vendor") ?? false);
     setState(() {
       _showVendorFields = result;
     });